1. Field of the Invention
The present invention relates to an antenna built-in type mobile phone.
2. Description of the Background Art
FIG. 1 is a schematic view of a general mobile phone in accordance with a conventional art.
As shown in the drawing, the conventional mobile phone includes a Helical antenna 1 fixedly installed at the upper end portion of a main body 3 and a monopol antenna 2 installed in a certain space of the mobile phone through the Helical antenna 1. For a telecommunication, the monopol antenna is pulled out, which has a length of λ/4.
When the user tries a telecommunication, current flows to the antenna, and electromagnetic wave is radiated toward a base station. In this respect, in case of using only the Helical antenna 1, without pulling out the monopol antenna 2, the resonant frequency of the antenna is adjusted with a called party. Meanwhile, in case of pulling out the monopol antenna 2 to increase the gain of the antenna, the resonant frequency is adjusted with a calling party.
Generally, downsizing of a mobile phone has a close relation with the size and the weight of the antenna. In line with the development of telecommunication techniques and increasing users' desire, mobile phones become compact and light rapidly, and in this respect, the antenna is paid much attention increasingly.
However. In order to build the monopol antenna in the main body of the mobile phone, a space is required in the mobile phone, which is disadvantageous in promotion of a compact and lightweight mobile phone.
In addition, since the antenna is fabricated through a number of processes, degrading the productivity.
Also, since the Helical antenna is installed to be outwardly protruded, it is inconvenient in that when users pull out the mobile phone, the antenna may be caught on a pocket of clothes or in a bag. In order to overcome the defects, in case of shortening the antenna, the frequency gain is reduced, degrading the performance of the mobile phone.